/// <summary>
 /// 系统应用的用户实体
 /// </summary>
 public class ApplicationUser : BaseModel
 {
  /// <summary>
  /// 用户名
  /// </summary>
  public string UserName { get; set; }
  /// <summary>
  /// 密码
  /// </summary>
  public string Password { get; set; }
  /// <summary>
  /// 邮件地址
  /// </summary>
  public string Email { get; set; }
 }

/// <summary>
 /// 系统上下文
 /// </summary>
 public class LightContext : DbContext
 {
  public LightContext(DbContextOptions<LightContext> options) : base(options)
  {
  }
  /// <summary>
  /// 系统应用用户
  /// </summary>
  public DbSet<ApplicationUser> ApplicationUser { get; set; }
  /// <summary>
  /// 角色表
  /// </summary>
  public DbSet<Role> Role { get; set; }
 }

Install-Package Microsoft.EntityFrameworkCore.SqlServer
Install-Package Microsoft.EntityFrameworkCore.Tools

<ItemGroup>
 <DotNetCliToolReference Include="Microsoft.EntityFrameworkCore.Tools.DotNet" Version="2.0.1" />
</ItemGroup>

dotnet ef migrations add InitLightDB

<PropertyGroup>
 <TargetFramework>netcoreapp2.0</TargetFramework>
 <RuntimeFrameworkVersion>2.0.3</RuntimeFrameworkVersion>
 </PropertyGroup>

public class DesignTimeDbContextFactory : IDesignTimeDbContextFactory<LightContext>
 {
  public LightContext CreateDbContext(string[] args)
  {
   var builder = new DbContextOptionsBuilder<LightContext>();
   builder.UseSqlServer("Server=(localdb)\\MSSQLLocalDB;Integrated Security=true;Initial Catalog=Light;");
   return new LightContext(builder.Options);
  }
 }

public static void ConfigApplicationUser(ModelBuilder modelBuilder)
  {
   modelBuilder.Entity<ApplicationUser>(m =>
   {
    m.Property(t => t.Email)
      .HasMaxLength(50);
    m.Property(t => t.UserName)
      .IsRequired()
      .HasMaxLength(50);
    m.Property(t => t.Password)
      .IsRequired()
      .HasMaxLength(20);
   });
  }

public class DesignTimeDbContextFactory : IDesignTimeDbContextFactory<LightContext>
 {
  public LightContext CreateDbContext(string[] args)
  {
   Directory.SetCurrentDirectory("..");//设置当前路径为当前解决方案的路径
   string appSettingBasePath = Directory.GetCurrentDirectory() + "/Light.AuthorityApi";//改成你的appsettings.json所在的项目名称
   var configBuilder = new ConfigurationBuilder()
    .SetBasePath(appSettingBasePath)
    .AddJsonFile("appsettings.json")
    .Build();
   var builder = new DbContextOptionsBuilder<LightContext>();
   //builder.UseSqlServer("Server=(localdb)\\MSSQLLocalDB;Integrated Security=true;Initial Catalog=Light;");
   builder.UseSqlServer(configBuilder.GetConnectionString("LightConnection"));
   return new LightContext(builder.Options);
  }
 }